When the BBC gives a platform to guests with "extremist" views, complaints usually follow.

Often, it is simply that a segment of the audience feels that those views are not properly challenged.

Sometimes, however, the guests themselves are deemed so extreme that some people argue they should not have been allowed on the show in the first place.

Newsnight found itself in the hot seat on Monday after an item featuring Abu Uzair and Abu Izzadeen, two Muslims who refused to condemn the suicide bombings in London.

The same programme also featured Asghar Bukhari, whose views have sparked complaints before.

Here, Newsnight assistant editor Ben Rich explains why the BBC needs to give such people a platform so their views can be understood and challenged.

We have received a large number of complaints about this broadcast, most objecting to Newsnight allowing people on air who support or refuse to condemn suicide bombing in the UK.

Abu Izzadeen said that suicide bombers "were praise-worthy"

Some other complaints concerned the use of Asghar Bukhari in the discussion, who condemned the suicide bombings in London, but does not similarly condemn them in Israel.

The current issue of extremism is a very difficult one for broadcasters, and sadly often causes offence.

It was our view that it was a legitimate part of our role to identify and demonstrate these problems, and discuss how they should be addressed.

While not many Muslims think that the suicide bombings in London were justified, clearly it requires only a few people to cause the mayhem we saw on 7 July, and could have seen again on 21 July.

We thought it an important contribution to the debate on extremism in Britain to lay out who these people are and challenge these views, and having done so to pursue the argument over whether the banning of these groups would be of any help.

Suicide bombing

The reporter, Richard Watson, was clear that these views are almost universally regarded as abhorrent, and challenged the interviewees. They were both members of a perfectly legal organisation - indeed, whether it should continue to be so was the issue.

The need to understand and report on these matters has taken precedence over the revulsion people might feel on listening to these views being expressed

I understand that some people do not agree that this sort of material should be broadcast.

All broadcasters faced a similar dilemma over interviews with members or supporters of the IRA (indeed for a period it was against the law to broadcast the voices of Sinn Fein representatives), and continue to face it with other national and international terrorist groups.

In the end, the need to understand and report on these matters has taken precedence over the revulsion people might feel on listening to these views being expressed.

This issue of the use of Bukhari Asghar is a little different.

He was invited onto the programme to discuss the issue of extremism here. He condemns the London bombings, however he is known not to feel the same about suicide bombing in Israel.

He is the official representative of a legal group which operates among the Muslim community here, and came on to make the argument against banning the group featured in Richard Watson's report.

Abu Uzair's views also upset some viewers

The issue is whether the BBC should specifically exclude anyone known to favour (or at least not to condemn) terrorist acts either here or elsewhere.

We do not operate such a policy of exclusion.

There are many things here or abroad that people may find abhorrent, but it has never been a condition of appearing on the BBC that interviewees' views must pass a test of, as it were, not agreeing with objectionable practices, or holding objectionable opinions.

Persuading people

In each individual case we have to weigh the importance of the issue being discussed, the relevance of the potential interviewee, and whether their views on matters not directly under discussion (although in this case related) render them an inappropriate participant.

We also have to decide if their view on the other matter needs to be brought into the open to give proper context to the actual discussion.

In this case we felt that his views on Israel did not invalidate his standing for the purpose we were using him for, nor did we feel it necessary to discuss suicide bombing in Israel as part of this discussion.

I am sorry this item annoyed people and I understand that with delicate questions of judgement like this one, we may not persuade people that our decision was right.